[llmllmllm]

The UK doesn't have exit checks.

[mmsc]

Of the ~50 countries I've been to in the past 10 years, The UK is the only one I remember which I did not need to show any ID when leaving. I thought it was strange because this is just one way countries catch overstays.

[chatmasta]

But what’s the point of catching an overstay if they’re leaving already? It’s more important to catch them when they try to re-enter (at which point you could have collected data from airlines to estimate whether they previously overstayed).

Exit checks are pretty pointless if there’s no violation that would lead to enforcement other than deportation (since the traveler is already self-deporting).

[zarzavat]

They get the records from the airlines. They don’t need to pay someone to stamp passports at the border to know who is overstaying.

[jowea]

Maybe it's a requirement for for air travel only? Why do all those countries bother? Surely they don't all have exit visa requirements?

[spullara]

When taking the Chunnel recently there are two passport checks on the way to the train, leaving UK and then 20 ft later entering France.